How do I motion track a camera when the scene contains more than one camera?
Rename the "sets" of photos, so that they are seen as a single image sequence with continuos numbering.

Track specific elements that are common in different "sets" of images.

Use "Join tracks" in places where the tracked items are not recognized, or change placement dramatically, become occluded, or re-appear.

Read the following links: Joining 2D tracking markers with an offset and Motion Tracking objects that go out of frame and re-enter later